Ethanolic extract of dried flower bud of Syzygium aromaticum L. (clove) was investigated to evaluate its antifungal activity against local fungal isolates causing post-harvest infections form potato and tomato. Four fungal isolates; Geotrichum candidum, Alternaria alternata, Fusarium oxysporum and Mucor hiemalis were identified. All fungal isolates were found to be inhibited by the extract; whereas the smallest inhibition zone) of S. aromaticum extract was 2.5% for M. hiemalis, A. alternata, G. candidum and 12.5% for F. oxysporum. Quantitative assessment of phytochemical compounds in clove plant revealed the presence of phenolic acids (20.80%); flavonoids (26.81 %); tannins (4.90%), saponins (2.60%), alkaloids (1.60%), total protein (17.83%), total carbohydrate (2.23%) and total oil (0.90%). Biochemical profile was revealed by GC/MS which detect 18 different chemical compounds. The major compounds were eugenol (17.27%), trans-caryophyllene (0.50%), humulene (3.33%), anthracenedione (3.35%), cedran-diol (0.61%), citroflex A (5.45%) and lucenin 2 (8.25%). TLC technique and different solvent systems were employed to select the proper one based on its capacity to isolate the maximum number of fluorescent spots in crude extract. Chloroform-acetone-butanol (CAB) 85:15:20 could efficiently separate three bands (A, B and C). Each detected band was individually screened for its antifungal activity against the isolated fungi. Only band C showed a significant antifungal activity. Mass spectroscopy (MS) was used to investigate characteristics, purity as well as expectation of both chemical formula and molecular weight of the isolated compounds; which finally proved that glucoside β-sitosterol was the main compound represented in fraction -C.